Cisco Systems, Inc. (NASDAQ:CSCO) is among the US companies that have expressed outrage at President Donald Trump’s decision to ban certain people from target countries from entering the United States for several months.

Other Silicon Valley heavyweights that have also criticized Trump’s immigration ban include Apple Inc. (NASDAQ:AAPL), Microsoft (NASDAQ:MSFT) and Alphabet Inc (NASDAQ:GOOGL). Executives of Tesla Motors Inc (NASDAQ:TSLA), Salesforce.com, Inc. (NYSE:CRM) and Facebook Inc (NASDAQ:FB) have also spoken against the move.

Concern over staff movement

As for Cisco, the company says banning certain people from entering the US is already having an effect on its employees. Trump issued an executive order barring citizens of majority Muslim countries such as Iran and Iraq from entering the US for 120 days.

Cisco is worried the ban will affect the movement of its employees. According to Cisco’s head for Australia and New Zealand, Ken Boal, a large part of the company’s workforce from around the world to go the US every year for meetings that are core to employment.

“Quite frankly the entire industry has concerns about how we’re going to work under this new environment,” said Boal.

Immigrants a boost to R&D

As for Apple, the company’s CEO Tim Cook said the company wouldn’t exist without immigrants coming to the US. Silicon Valley benefits from the inputs of immigrants in areas such as research and development, which tech executives are worried would suffer if Trump’s travel ban succeeds.

A federal judge has already suspended parts of Trump’s executive order, but the major threat companies see in the order remains.

Support for affected employees

Several Silicon Valley companies have pledged support, including legal defense, for their employees affected by Trump’s travel ban. Others like Google have already set aside funds to fight Trump’s controversial immigration order.

Cisco’s shares have gained nearly 30% over the last 12 months. However, the stock retreated 0.4% to $30.72 in the last session.